The Comic Relief star insists a lack of roles for black and Asian talent in British TV is increasingly forcing them to seek work in the US, where they can land big roles.

Lenny, 55, says more black actors got work in the 1970s because they were “patronised” but fears things are getting worse.

He said: “We had a good 1970s. That was because of patronage. Whatever minority you come from, there’s often a bloke – generally white, male, middle-class and Oxbridge-educated – who says, ‘I like you, I’m going to take you under my wing’.”

“The problem is that when they go, you go too – or you have to realign or find another mentor.”

Lenny spoke last week as he attended a talk by the Royal Television Society which heard how opportunities for non-whites working in areas such as UK high-end TV drama and comedy had diminished in recent years.

Lenny said action is needed to reverse the situation. He suggested introducing the kind of quotas for black actors’ representation in UK TV that regulators had adopted to force broadcasters to make more programmes outside London.

Asian actor Sudha Bhuchar highlighted the problem that middle-aged female actors like her experience. The former EastEnders star said: “I haven’t had an audition all year.”